Neurological Aspects of Arachnoiditis

by Dr. Sarah Smith

IMPORTANT NOTE:

The information in this article is for general purposes only and is NOT a substitute for medical consultation. You should NEVER attempt to self-diagnose.

 

Part Three:

PAIN, PINS AND NEEDLES AND OTHER SENSORY PROBLEMS

TYPES OF PAIN:

In arachnoiditis, the predominant pain tends to be neuropathic (neurogenic), i.e. arising from nerve damage. However, one must also bear in mind that there may be musculoskeletal pain both from the original underlying spinal problem and also as a secondary feature due to muscle tension in response to unalleviated pain. So there may be a variety of different types of pain experienced.

The commonest ones appear to be:

• Burning          
• Shooting/stabbing
• Deep aching
• Muscle spasm
• Joint pain
• Headache
• Abdominal pain

PINS AND NEEDLES

The term paraesthesiae encompasses a wide variety of abnormal sensory experiences, which tend to be described as:

• Burning
• Tingling
• Prickling
• Feeling of warmth
• Feeling of cold
• Trickling water
• Insects crawling on the skin
• Insect bite
• Itching

These sensations can arise from central nervous system abnormalities or peripheral nerve damage (peripheral neuropathy is a common cause).

They are most commonly experienced in the feet, hands, arms and legs, but can occur anywhere on the body. 

SUMMARY:

There are 3 important points to remember:

1. It is quite possible to have pain or pins and needles without any apparent physical deficit on examination.
2. If pain has become centralised then the areas of sensory abnormality may be more widespread than would be expected from a particular nerve root being affected.
3. One of the features of neuropathic pain is that it may be felt in numb areas.

SWEATING:

Excessive sweating (hyperhidrosis or diaphoresis) occurs when the sympathetic nervous system (part of the autonomic nervous system which regulates involuntary body functions) is running on overdrive. This seems to be a common problem in arachnoiditis, and is probably in part due to direct effects on the sympathetic chain, which runs alongside the spine, and also partly due to the chronic stress of unremitting pain. A further reason might be that arachnoiditis patients can experience intermittent low grade fevers and the sweating (especially at night) might be related to this. Note that sweating can occur regardless of environmental temperature (even in the cold) or emotional state, cold sweats are often quite profuse.

The best bet is to implement some general measures:

Firstly, avoid overheating your home or going to places which are likely to be overheated. If you can, avoid dealing with large temperature fluctuations.

Reduce your caffeine intake. 

For menopausal symptoms, HRT can be successful.

·         Bathe frequently, but avoid very hot baths/showers as this may well trigger a burst of sympathetic activity and thus profuse sweating.

• Shave underarm hair.
• Change clothes frequently.
• Wear loose-fitting clothes of natural fibers, such as cotton.
• Use underarm sweat shields.
• Use antiperspirants and deodorants.
• Use drying powders.
• Wear cotton socks.
• Wear leather shoes or sandals. Don't use man-made materials.
• Try to use pure cotton bedsheets and nightclothes
• Leave a window ajar at night to allow some air circulation

1. Topical: antiperspirants such as aluminium chloride(20-25% in 70-90% alcohol) applied in the evening 2-3 times a week. However, may become less effective over time (months) and there may be a high incidence of skin irritation. Anhydrol Forte, Driclor solution and ZeaSORB are some of the preparations available.
2. Drugs: no specific treatment, but anticholinergic drugs, which may have been prescribed for pain relief (amitriptyline for example) or bladder control (oxybutinin) may have this beneficial side effect (other less pleasant ones include dry mouth: ‘cotton tongue’, and difficulty in focussing).
3. Iontophoresis: low intensity electric current (15-18mA) applied to the palms or soles immersed into electrolyte solution. Initially requires several 20 minute sessions per week, gradually increasing the interval between treatments to 1-2 weeks. Results vary, patients with light-moderate sweating may have good results; some find the regime troublesome, time-consuming, and quite expensive. This method is difficult to apply to the armpit and cannot be used for facial sweating. Side effects include: burning, electric shock, discomfort, skin tingling, skin rash. Sweating will return if the treatment is discontinued.
4. Botulinum toxin injections: invasive so not recommended. (lasts 6 weeks-12 months then has to be repeated)
5. Laser therapy: has not been found to be beneficial.
6. Hypnosis: not been found effective.
7. Sympathectomy: surgical interruption of the nerve impulses from the thoracic ganglia (‘endoscopic thoracic symapthectomy) : reserved for severe, refractory cases. Although success rates of ETS are over 90% for hand hyperhidrosis and 75-80% for armpit hyperhidrosis, one of the commonest side effects (in around 50-60% of patients) is ‘compensatory sweating’ : the body attempts to compensate for the artificially reduced sweating in the upper chest, back and arms by increasing sweat from face, abdomen, lower back, buttocks and feet. A further 5-10% of patients may develop ‘gustatory sweating’ which is an increased sweat production when eating. Horner’s syndrome may occur in about 1%.
8. Axillary sweat gland removal: z-plasty excision of the sweat glands under the arm; again, an invasive technique so not recommended except for severe cases.

AUTONOMIC DYSFUNCTION

Symptoms:

• Postural dizziness
• Reflux oesophagitis and delayed gastric emptying (latter may cause vomiting in the morning)
• Nocturnal diarrhoea
• Post-gustatory sweating (after meals)
• Bladder dysfunction/urinary retention: (note: these are dealt with fully in other articles)
• Impotence
• Pupil abnormalities
• Thermal irregularities : difficulties with temperature regulation: a common problem
• Skin colour abnormalities (mottled)

Peripheral circulation abnormalities: Raynaud type syndrome: vasoconstriction of blood vessels in hands and feet: poor circulation. Changes in temperature cause a 3-phase colour sequence: white>blue>red. Can also affect nose, ears and tongue. Repetitive movements such as typing may worsen the symptoms. Overheating the affected part may also make matters worse

Treatment:

(a)     Postural dizziness: elastic stockings, fludrocortisone 0.1-0.3mg daily, ephedrine, midodrine.

(b)     Reflux/delayed gastric emptying: metoclopramide 10mg before meals

(c)     Nocturnal diarrhoea: metoclopramide 10mg 8 hourly

(d)     Post-gustatory sweating: propantheline hydrobromide before meals

(e)     Bladder dysfunction/urinary retention: specialist assessment and treatment (see appropriate article*)

(f)      Impotence: specialist assessment and treatment (see appropriate article*)

(g)     Raynaud’s: Avoidance of caffeine and nicotine can be helpful as they both act as vasoconstrictors. Medication: nifedipine, prazosin. topically-applied nitric oxide gel, (a study in 1999 showed it tripled the blood flow to patients’ fingers, to the extent that it approached that found in untreated healthy volunteers) fish oil, Evening primrose oil (EPO), Gingko biloba(but note: increased risk of bleeding abnormalities, especially if taken with anti-inflammatory medication including aspirin). Invasive treatments such as a sympathectomy (usually a toxic chemical such as phenol is injected into a sympathetic ganglion to destroy the nerve), are not advised by the Arachnoiditis Trust.

TINNITUS:

This term refers to noises heard ‘in the ears’ or ‘in the head’ which don’t come from an external source.

• Buzzing
• Ringing
• Whistling
• Hissing
• Pulsing

There may also be heightened sensitivity to external sounds : hyperacusis

The Jastreboff model is as yet unfamiliar with many medical practitioners. The basic tenet of this model is that tinnitus is not an ear problem, but a brain one, and that retraining this part of the brain is feasible: this is known as Tinnitus Retraining Therapy. The goal of this therapy is to habituate the patient to the tinnitus.

The first vital step is to understand that the subconscious parts of the brain which act as ‘filters’ and which focus on weak electrical signals from the inner ear need to be retrained. This is NOT to suggest that tinnitus is a psychological problem. However, it must be noted that psychological distress (anxiety, agitation, anger) often accompany tinnitus: these emotional responses are targeted in the retraining strategy.

What retraining involves:

1. a thorough examination by an ear specialist
2. development of a full understanding of what happens in the ear and the brain to cause tinnitus
3. correction of any hearing loss*
4. acceptance that the sounds of tinnitus  are natural sounds and it is our interpretation of them which makes them seem distressing

habituation of reaction: the initial stage of retraining

habituation of perception: tinnitus becomes quieter and eventually disappears or becomes part of the natural background ‘sound of silence’.

 

Retraining therapy takes time, about 2 years.

* hearing loss will cause a tendency to strain to hear, thereby increasing the amplification of sound signals, increasing the sensitivity of the brain and thus the ease with which tinnitus is picked up.

 

GAIT ABNORMALITIES:

 

• Impaired range of motion (usually joint damage)
• Impaired muscle activity: weakness, spasticity, disorders of timing
• Pain
• Sensation loss

These problems cause:

• Instability
• Reduced ability to move
• Increased cost in terms of energy expended
• Need to compensate
• Joint strain
• Muscle overuse
• Fatigue

FOOT DROP

In some arachnoiditis patients with leg weakness, this can progress to the point where the muscles in the top part of the ankle are too weak to hold the foot at the 90 degree angle, this causing difficulties in walking. The toes tend to catch on the floor, which leads to trips and falls.

Foot drop occurs most commonly if there is arachnoiditis at levels L4/5 and L5/S1 because this is the spinal level from which the innervation of the common peroneal nerve arises. This nerve supplies both sensory and motor innervation to the top of the foot (dorsum) and toes.

Whilst people may be aware of spinal problems at the relevant levels (arachnoiditis, epidural fibrosis, disc herniation etc.), there must be a thorough investigation to rule out other sites of nerve compression and causes such as diabetes, hyperthyroidism (pretibial myxoedema) and Polyarteritis nodosa.

Physiotherapy and/or splints may be of assistance in this condition.

 

WEAKNESS

Weakness is a broad term which can have a variety of meanings. It may be used to refer to generalised fatigue or malaise; or it may be more specifically muscle weakness.

People with arachnoiditis often suffer from fatigue (76% in the 1999 survey).

They also frequently have muscle weakness, which can be mild, moderate or severe. 82% of the 1999 Survey respondents reported weakness as a symptom.

In arachnoiditis, there may well be nerve root damage, at one or several spinal levels.

Weakness will tend to occur in the same areas as pain sensation. The commonest areas are in the foot and calf. Also buttock muscles may be affected, with muscle wasting. If there is cervical (neck) pathology, then spasticity may be evident.

Other causes:

Disuse atrophy

Muscle wasting may be due to disuse/immobility.

Potassium abnormality:

Either high(hyperkalaemia) or low (hypokalaemia) potassium can cause muscle weakness.

Hyperkalaemia is most commonly caused by excessive use of salt substitutes.

Hypokalaemia: low blood potassium seems to occur in a number of people with arachnoiditis, but it is not specific to this condition as it also occurs in other people with chronic illness. Causes include:

• Poor dietary intake: Tea and toast diet; excessive alcohol intake
• Gastrointestinal loss: Protracted vomiting/ diarrhoea; laxative abuse
• Excessive sweating
• Excess mineralocorticoid effect: Primary or secondary hyperaldosteronism
• Excessive glucocorticoid hormones (Cushing’s syndrome); Excessive ACTH (endocrine disorders)*
• Licorice abuse
• Renal tubular acidosis ( a kidney disorder)
• Diuretic therapy (water tablets)
• Carbenicillin, penicillin therapy
• Leukaemias
• Hyperthyroidism: potassium levels are low in patients with hyperthyroidism

*note that in chronic pain conditions, the stress involved may lead to a sustained increase in stress hormones, of which cortisol ( a glucocorticoid) is one.

 

MISCELLANEOUS CONDITIONS:

 

Plantar neuroma (also known as Morton’s neuroma) is a relatively common peripheral neuropathy. Also known as plantar digital neuritis(intermetatarsal/interdigital neuritis IDN), a term which describes the condition more accurately as it involves interdigital (between the toes) nerve on the sole of the foot. It tends to be on one foot, usually between the 3rd and 4th. toes.

The symptoms are: agonising pain in the sole after walking/standing in closed shoes for a variable period of time; relief can only be obtained by stopping, sitting down, removing the footwear and resting and/or massaging the foot. The pain tends to be well localised: more diffuse pain is likely to be from a different condition.

Typical descriptions are: “like walking on a hot pebble”; “having a hot poker thrust between the toes.”

Mild forms present with burning pain and occasional numbness or tingling.

By contrast, PLANTAR FASCIITIS is a form of heel pain. It involves inflammation of the thick band of tissue in the sole of the foot, called the plantar fascia. This strong tissue connects the heel to the base of the toes, maintaining the arch of the foot. This inflammation tends to occur either after prolonged standing or from repetitive stress such as walking/running/athletic activity. (none of which are particularly likely in someone with arachnoiditis!)

Heel pain can also be caused by nerve entrapment, stress fracture, heel spur (calcaneal spurs: bony outgrowth) or as a part of inflammatory conditions such as rheumatoid arthritis or gout. Bearing in mind the probable link between arachnoiditis and autoimmune disorders, it may be that plantar fasciitis is a feature of arachnoiditis.

Foot care:

If you have numbness, you are less likely to notice injuries or sores, which could become infected or ulcerated if left untended.

The following are useful tips:

1. Check your feet every day, using a mirror if you can’t bend to look closely, or ask someone else to do it.
2. Wash your feet every day in warm water, checking the temperature first using an elbow (just as they suggest for a baby bath!)
3. Always dry your feet thoroughly, especially between the toes
4. Your feet may have become wider and flatter as a result of small muscles becoming weaker. It is vital to wear comfortable shoes; cool ones for warm weather and good warm socks in colder weather (circulation may be poor: reduce the risk of chilblains or the impact of Raynaud’s*)
5. Use shoe inserts or buy shoes with air soles: they may cost more but it is well worth it.
6. Visit a chiropodist for treatment of corns/calluses and also for advice on shoes: he/she may take a plaster cast of your foot and make special shoes inserts for your individual needs.
7. Avoid walking round barefoot
8. When cutting toenails, cut straight across to avoid leaving sharp edges
9. Avoid sitting with your legs/ankles crossed: it cuts down your blood supply and can even cause further nerve damage such as pressure palsies

If you get a sore, seek medical attention to ensure necessary treatment is implemented.